Method for controlling humidity in a domestic refrigerator, and refrigerator adapted to carry out such method

Abstract

A method for controlling the humidity inside a refrigerator, having at least a cavity and a refrigeration circuit including an evaporator and a compressor, comprising the step of measuring the relative humidity level inside the cavity, measuring the temperature of the evaporator and feeding the above measured values to a control algorithm capable of driving the refrigeration circuit in order to maintain substantially constant the average level of relative humidity and corresponding to a set value.

1. A method for controlling the humidity inside a refrigerator, the refrigerator comprising at least a cavity and a refrigeration circuit including a fan inside the cavity for allowing a forced air circulation inside the cavity, an evaporator and a compressor, the method comprising:
 measuring, directly or indirectly, a relative humidity level inside the cavity; 
 measuring, directly or indirectly, a temperature of the evaporator; and 
 feeding the relative humidity level and evaporator temperature to a control algorithm capable of driving the refrigeration circuit in order to maintain an average level of relative humidity substantially constant and corresponding to a set value, wherein the humidity is controlled inside the refrigerator cavity by acting on the compressor and the fan so that a cooling cycle is provided which is composed of three main phases: 
 a cooling storage phase in which the fan is off and the compressor is on; 
 a cooling distribution phase in which the fan is on with the compressor on until the evaporator has reached a first predetermined temperature; and 
 a warming phase in which the compressor is off, the evaporator has reached a second predetermined temperature higher than the first predetermined temperature and the fan is on or off according to the relative humidity level inside the cavity compared to the set value. 
 
     
     
       2. The method according to  claim 1 , wherein humidification of the refrigerator cavity is provided during the cooling distribution phase or during the warming phase by switching on the fan when a time derivative of the evaporator temperature is greater than a fixed positive threshold. 
     
     
       3. The method according to  claim 2 , wherein dehydration of the refrigerator cavity is provided by switching on the fan during the cooling storage phase or the cooling distribution phase when the time derivative is lower than a pre-determined negative threshold. 
     
     
       4. A method for controlling the humidity inside a refrigerator, the refrigerator comprising at least a cavity and a refrigeration circuit including an evaporator and a compressor, the method comprising:
 measuring, directly or indirectly, a relative humidity level inside the cavity; 
 measuring, directly or indirectly, temperature of the evaporator; and 
 feeding the relative humidity level and evaporator temperature to a control algorithm capable of driving the refrigeration circuit in order to maintain an average level of relative humidity substantially constant and corresponding to a set value, wherein the refrigeration circuit is driven according to the following steps:
 if the relative humidity level is lower than the set value and if the evaporator temperature is lower than a predetermined value, driving the refrigeration circuit in order to increase the evaporator temperature in order to allow a thawing of frost accumulated on the evaporator; and 
 if the relative humidity level is higher than the set value and if the evaporator temperature is higher than 0° C., driving the refrigeration circuit in order to decrease the evaporator temperature in order to allow a condensation and frosting of water vapour on the evaporator. 
 
 
     
     
       5. A refrigerator comprising:
 a cavity; 
 a refrigeration circuit including an evaporator, a compressor and a fan adapted to create air circulation inside the cavity; 
 a humidity sensor inside the cavity; 
 a temperature sensor for detecting a temperature of at least one of an inside of the cavity and the evaporator; and 
 an electronic control unit for driving the refrigeration circuit in order to keep the humidity level substantially constant and corresponding to a predetermined set value, wherein the electronic control unit is adapted to perform the following steps:
 if the relative humidity level is lower than the set value and if the temperature is lower than a predetermined value, driving the refrigeration circuit in order to increase the temperature in order to allow a thawing of frost accumulated on the evaporator; 
 if the relative humidity level is higher than the set value and if the temperature is higher than 0° C., driving the refrigeration circuit in order to decrease the temperature in order to allow a condensation and frosting of water vapour on the evaporator. 
 
 
     
     
       6. A refrigerator comprising:
 a cavity; 
 a refrigeration circuit including an evaporator, a compressor and a fan adapted to create air circulation inside the cavity; 
 a humidity sensor inside the cavity; 
 a temperature sensor for detecting a temperature of at least one of an inside of the cavity and the evaporator; and 
 an electronic control unit for driving the refrigeration circuit in order to keep the humidity level substantially constant and corresponding to a predetermined set value, wherein the electronic control unit is adapted to drive the compressor and the fan so that a cooling cycle is provided which is composed of three main phases: 
 a cooling storage phase in which the fan is off and the compressor is on; 
 a cooling distribution phase in which the fan is on with the compressor on until the evaporator has reached a first predetermined temperature; and 
 a warming phase in which the compressor is off, the evaporator has reached a second predetermined temperature higher than the first predetermined temperature and the fan is on or off according to a level of humidity inside the cavity compared to the set value.